ENH: Multi-component vmin, vmax

itkwidgets/widget_viewer.py

@@ -215,12 +215,12 @@ class Viewer(ViewerParent):
                   help="Region of interest: [[lower_x, lower_y, lower_z), (upper_x, upper_y, upper_z]]")\
         .tag(sync=True, **array_serialization)\
         .valid(shape_constraints(2, 3))
-    vmin = CFloat(
+    vmin = List(trait=CFloat(),
         default_value=None,
         allow_none=True,
         help="Value that maps to the minimum of image colormap.").tag(
         sync=True)
-    vmax = CFloat(
+    vmax = List(trait=CFloat(),
         default_value=None,
         allow_none=True,
         help="Value that maps to the maximum of image colormap.").tag(
@@ -345,6 +345,14 @@ def __init__(self, **kwargs):  # noqa: C901
             proposal = {'value': kwargs['cmap']}
             cmap_list = self._validate_cmap(proposal)
             kwargs['cmap'] = cmap_list
+        if 'vmin' in kwargs and kwargs['vmin'] is not None:
+            proposal = {'value': kwargs['vmin']}
+            vmin_list = self._validate_vmin(proposal)
+            kwargs['vmin'] = vmin_list
+        if 'vmax' in kwargs and kwargs['vmax'] is not None:
+            proposal = {'value': kwargs['vmax']}
+            vmax_list = self._validate_vmax(proposal)
+            kwargs['vmax'] = vmax_list
         self.observe(self._on_geometries_changed, ['geometries'])
         have_label_map = 'label_map' in kwargs and kwargs['label_map'] is not None
         if have_label_map:
@@ -587,6 +595,26 @@ def _validate_cmap(self, proposal):
         else:
             return [value]
 
+    @validate('vmin')
+    def _validate_vmin(self, proposal):
+        value = proposal['value']
+        if value is None:
+            return None
+        elif isinstance(value, list):
+            return value
+        else:
+            return [value]
+
+    @validate('vmax')
+    def _validate_vmax(self, proposal):
+        value = proposal['value']
+        if value is None:
+            return None
+        elif isinstance(value, list):
+            return value
+        else:
+            return [value]
+
     @validate('point_set_colors')
     def _validate_point_set_colors(self, proposal):
         value = proposal['value']
@@ -807,13 +835,13 @@ def view(image=None,  # noqa: C901
     label_map_blend : float, default: 0.5
         Label map blend with intensity image, from 0.0 to 1.0.
 
-    vmin: float, default: None
-        Value that maps to the minimum of image colormap. Defaults to minimum of
-        the image pixel buffer.
+    vmin: list of floats, default: Minimum of the image pixel buffer
+        Value that maps to the minimum of image colormap. A single value
+        can be provided or a list for multi-component images.
 
-    vmax: float, default: None
-        Value that maps to the minimum of image colormap. Defaults to maximum of
-        the image pixel buffer.
+    vmax: list of floats, default: Maximum of the image pixel buffer
+        Value that maps to the minimum of image colormap.  A single value can
+        be provided or a list for multi-component images.
 
     cmap: list of strings
             default:

js/lib/viewer.js

@@ -798,13 +798,21 @@ const ViewerView = widgets.DOMWidgetView.extend({
 
     const onChangeColorRange = (component, colorRange) => {
       const vmin = this.model.get('vmin')
-      if (colorRange[0] !== vmin) {
-        this.model.set('vmin', colorRange[0])
+      if (vmin === null) {
+        vmin = []
+      }
+      if (colorRange[0] !== vmin[component]) {
+        vmin[component] = colorRange[0]
+        this.model.set('vmin', vmin)
         this.model.save_changes()
       }
       const vmax = this.model.get('vmax')
-      if (colorRange[1] !== vmax) {
-        this.model.set('vmax', colorRange[1])
+      if (vmax === null) {
+        vmax = []
+      }
+      if (colorRange[1] !== vmax[component]) {
+        vmax[component] = colorRange[1]
+        this.model.set('vmax', vmax)
         this.model.save_changes()
       }
     }
@@ -1514,18 +1522,24 @@ const ViewerView = widgets.DOMWidgetView.extend({
   vmin_changed: function () {
     const vmin = this.model.get('vmin')
     if (vmin !== null && this.model.hasOwnProperty('itkVtkViewer')) {
-      const colorRange = this.model.itkVtkViewer.getColorRange(0).slice()
-      colorRange[0] = vmin
-      this.model.itkVtkViewer.setColorRange(0, colorRange)
+      const rendered_image = this.model.get('rendered_image')
+      for (let component = 0; component < rendered_image.imageType.components; component++) {
+        const colorRange = this.model.itkVtkViewer.getColorRange(component).slice()
+        colorRange[0] = vmin[component]
+        this.model.itkVtkViewer.setColorRange(component, colorRange)
+      }
     }
   },
 
   vmax_changed: function () {
     const vmax = this.model.get('vmax')
     if (vmax !== null && this.model.hasOwnProperty('itkVtkViewer')) {
-      const colorRange = this.model.itkVtkViewer.getColorRange(0).slice()
-      colorRange[1] = vmax
-      this.model.itkVtkViewer.setColorRange(0, colorRange)
+      const rendered_image = this.model.get('rendered_image')
+      for (let component = 0; component < rendered_image.imageType.components; component++) {
+        const colorRange = this.model.itkVtkViewer.getColorRange(component).slice()
+        colorRange[1] = vmax[component]
+        this.model.itkVtkViewer.setColorRange(component, colorRange)
+      }
     }
   },